The Universal Serial Bus (USB) specification describes a uniform data transmission protocol for use when transmitting data over a Universal Serial Bus. When fully compliant, USB controllers conform to the USB specification by implementing all of the functionality described by the USB specification. Although the use of fully compliant USB controllers is attractive because they can perform any activity described in USB specification, they may be complex and their incorporation into many USB hosts may be costly and an inefficient use of system resources. Thus the ability to do anything described in USB specification comes at the cost of being able to do a few simple things efficiently.